U.S. patent application Ser. Nos. 07/298,259 and 07/193,852 disclose a transition adapter which is crimped onto a flat power cable by penetrating the insulation covering the cable's conductor and also shearing through the conductor at a plurality of locations. The cable is of the type entering commercial use for transmitting electrical power of for example 75 amperes nominal, and includes a flat conductor one inch wide and about 0.020 inches thick with an extruded insulated coating of about 0.004 to 0.008 inches thick over each surface with the cable having a total thickness averaging about 0.034 inches. One embodiment of the transition adapter is stamped and formed of sheet metal and in one embodiment includes a pair of opposing plate sections disposed along respective major surfaces of the cable and including opposing termination regions extending transversely across the cable. Each terminating region includes a transverse array of alternating shearing wave shapes and relief recesses of equal width, the relief recesses defined by arcuate projections extending away from the cable-proximate side, and the wave shapes extending outwardly from the cable-proximate side and toward relief recesses in the opposed plate section. Each shearing wave shape has a transverse crest between parallel side edges, and the side edges of the corresponding relief recesses are associated with the wave side edges to comprise pairs of shearing edges, preferably with zero clearance. When the plate sections are pressed against a cable section disposed therebetween the crests of the wave shapes initiate cable shearing by their axially oriented side edges cutting through the cable insulation and into and through the metal conductor. The wave shapes extrude the sheared cable strips outwardly into the opposing relief recesses as the shears propagate axially along the cable for limited distances, forming a series of interlocking wave joints with the cable while exposing newly sheared edges of the cable conductor for electrical connection therewith.
Further with regard to the transition adapter of the above applications, fastened to the outwardly facing surface of the plate sections at the terminating regions are respective inserts of low resistance copper. The inserts have adapter-facing surfaces conforming closely to the shaped outer surface of the terminating region, with alternating wave shapes and apertures disposed outwardly of and along the adapter wave shapes and relief recesses. Upon termination the wave joints are within the insert apertures, and the sheared edges of the adjacent conductor strips and of the adapter wave shapes which formed the sheared strips are adjacent to side surfaces of the copper insert apertures. A two-step staking process is preferred: in a first step the wave joints are split axially so that portions of each arcuate shape of both adapter plate sections are forced inwardly against the adjacent sheared conductor strip of the respective wave joint to define spring fingers whose ends pin the conductor strip against the opposing wave crest to store energy in the joint; and in the second step a staking process deforms the insert between the sheared strips to deform the copper against the sheared conductor and wave shape edges, forming gas-tight, heat and vibration resistant electrical connections with the cable conductor and with the transition adapter, so that the inserts are electrically in series at a plurality of locations between the conductor and the adapter.
A contact section is integrally included on the transition adapter enabling mating with corresponding contact means of a electrical connector, or a bus bar, or a power supply terminal, for example, and can include a plurality of contact sections to distribute the power to a corresponding plurality of contact means if desired. A housing or other dielectric covering can be placed around the termination as desired, such as is disclosed in U.S. patent applications Ser. Nos. 07/234,063 filed Aug. 18, 1988 and 07/338,790 filed Apr. 14, 1989, both assigned to the assignee hereof.
Also entering commercial acceptance is a dual conductor flat cable, wherein a pair of parallel spaced coplanar flat conductor strips having insulation extruded therearound define power and return paths for electrical power transmission. One method has been devised as disclosed in U.S. Pat. No. 4,241,498 which involves a member associated with one of the two conductors having upper and lower sections joined at a tab. The upper and lower sections are brought along the upper and lower surfaces of the conductor from the side of the cable so that the tab is disposed laterally of the cable. The upper and lower sections have semicylindrical metallic jaws having alternating grooves and lands with the grooves of one jaw adapted to receive thereinto the lands of the opposing jaw when the upper and lower sections are pressed against the conductor. The lands shear strips of the conductor and extrude the sheared strips into the opposing grooves, in a punch and die process. After termination the sheared conductor edges are disposed adjacent sides of the grooves of the semicylindrical jaws to form electrical connections therewith. The tab extends laterally from the cable and is exposed for electrical engagement therewith by another electrical article. The other conductor may be similarly terminated at a nearby location.
In another method for terminating multiconductor flat cable for undercarpet use, an adapter has a plurality of terminals for respective conductors of the cable joined by a strip of dielectric polymeric material, each terminal having an array of upstanding ribs punched out of the plane of the terminal and having vertical sheared edges. The adapter is to be disposed across the cable and the ribs will extend axially along the cable. The cable is prepared by punching therethrough an array of slots corresponding to the ribs, and each slot has a width identical to a rib width. The strip of terminals is placed across the cable so that the ribs extend through the slots and extend beyond the far cable surface far enough so that a tough metal foil tab or strip may be placed under each rib array along the far cable surface. The ribs are then flattened back into the slots, and the foil is thereby pressfitted or wedged between the rib edges and the sheared conductor edges defining the slots forming electrical connections between the terminals and the respective conductors. Solder is placed in the voids of the terminals left from forming the ribs, which also may contribute to a good electrical connection when reflowed to join the terminal to adjacent surfaces of the metal foil tab portions pressed into the cable slots.
It is desired to provide a method for interconnecting single conductor and especially dual conductor flat power cables by forming cable taps and splices.
It is also desired that such interconnection be relatively simple and provide for assured electrical connections which remain gas-tight and heat and vibration resistant over time.